= Inertial-diffusive scalar range
{title2=$S_C(r)\simeq\epsilon_cr^2/(3\alpha)$}
For scalar diffusivity much larger than <kinematic viscosity>, scalar diffusion dominates at lengths between the Kolmogorov and scalar cutoff scales. The velocity may still have inertial-range variations, but the scalar is smooth to leading order. The leading isotropic <scalar structure function> is quadratic, with coefficient fixed by the mean-square gradient and the <scalar dissipation rate>, rather than by a continuing inertial-convective two-thirds law.
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